1. Field of the Invention
The invention relates to a projecting device, and more particularly to a projecting device with a keystone correction function.
2. Description of the Related Art
With the highly developed technology in the industry, the quality of the presentation apparatus in the meeting room is greatly improved, wherein the projector plays an important role in the meeting because its signal quality directly influences the visual feelings of all the attendant members.
In order to enable the projector to project the frame on a proper height, the angle of the projector has to be adjusted to meet the actual requirement of the meeting room. In order to satisfy various requirements of different meeting rooms, the angle of the projector has to be frequently adjusted. However, when the angle is adjusted, the frame may have keystone distortion. Thus, the keystone correction has to be performed to recover the keystone frame to a fairly upright frame and to reduce the distortion.
The conventional keystone correction is implemented using a horizontal integrated circuit (hereinafter referred to as IC). The horizontal IC may detect the angle offset of the projector in the horizontal axis (x-axis) or vertical axis (y-axis). Then, the system performs computations to automatically execute the keystone correction procedure according to the offset measured by the horizontal IC. Although the conventional method may solve the problem of keystone distortion, the price of the horizontal IC is relatively high and is a great loading to enterprises or customers when the price is added to the manufacturing cost. Consequently, it is important to develop a technology device to replace the horizontal IC, reduce the cost, and increase the product competitiveness.